Updated get_element/side_fe comments
Updated get_element/side_fe comments

To discuss why we default to this->get_dim() for the dimension
rather than this->get_elem_dim().

Provide example of the aforementioned call.

svallaghe/libmesh,jwpeterson/libmesh,pbauman/libmesh,vikramvgarg/libmesh,90jrong/libmesh,coreymbryant/libmesh,balborian/libmesh,libMesh/libmesh,cahaynes/libmesh,giorgiobornia/libmesh,benkirk/libmesh,BalticPinguin/libmesh,capitalaslash/libmesh,jwpeterson/libmesh,90jrong/libmesh,permcody/libmesh,friedmud/libmesh,dmcdougall/libmesh,capitalaslash/libmesh,svallaghe/libmesh,friedmud/libmesh,vikramvgarg/libmesh,giorgiobornia/libmesh,friedmud/libmesh,benkirk/libmesh,cahaynes/libmesh,vikramvgarg/libmesh,giorgiobornia/libmesh,90jrong/libmesh,dknez/libmesh,vikramvgarg/libmesh,dknez/libmesh,vikramvgarg/libmesh,cahaynes/libmesh,libMesh/libmesh,capitalaslash/libmesh,hrittich/libmesh,coreymbryant/libmesh,dmcdougall/libmesh,dmcdougall/libmesh,friedmud/libmesh,benkirk/libmesh,dschwen/libmesh,BalticPinguin/libmesh,roystgnr/libmesh,BalticPinguin/libmesh,balborian/libmesh,vikramvgarg/libmesh,aeslaughter/libmesh,balborian/libmesh,cahaynes/libmesh,dschwen/libmesh,permcody/libmesh,svallaghe/libmesh,pbauman/libmesh,jwpeterson/libmesh,aeslaughter/libmesh,coreymbryant/libmesh,svallaghe/libmesh,jwpeterson/libmesh,aeslaughter/libmesh,hrittich/libmesh,90jrong/libmesh,dknez/libmesh,pbauman/libmesh,cahaynes/libmesh,pbauman/libmesh,svallaghe/libmesh,aeslaughter/libmesh,pbauman/libmesh,dschwen/libmesh,balborian/libmesh,vikramvgarg/libmesh,jiangwen84/libmesh,friedmud/libmesh,jiangwen84/libmesh,hrittich/libmesh,cahaynes/libmesh,benkirk/libmesh,pbauman/libmesh,90jrong/libmesh,capitalaslash/libmesh,jiangwen84/libmesh,roystgnr/libmesh,90jrong/libmesh,permcody/libmesh,permcody/libmesh,BalticPinguin/libmesh,hrittich/libmesh,aeslaughter/libmesh,libMesh/libmesh,aeslaughter/libmesh,roystgnr/libmesh,90jrong/libmesh,roystgnr/libmesh,roystgnr/libmesh,permcody/libmesh,balborian/libmesh,dmcdougall/libmesh,dschwen/libmesh,hrittich/libmesh,jiangwen84/libmesh,giorgiobornia/libmesh,balborian/libmesh,dknez/libmesh,libMesh/libmesh,roystgnr/libmesh,jwpeterson/libmesh,90jrong/libmesh,cahaynes/libmesh,dknez/libmesh,svallaghe/libmesh,benkirk/libmesh,hrittich/libmesh,BalticPinguin/libmesh,libMesh/libmesh,permcody/libmesh,libMesh/libmesh,svallaghe/libmesh,permcody/libmesh,capitalaslash/libmesh,vikramvgarg/libmesh,libMesh/libmesh,giorgiobornia/libmesh,jiangwen84/libmesh,libMesh/libmesh,jiangwen84/libmesh,giorgiobornia/libmesh,friedmud/libmesh,pbauman/libmesh,svallaghe/libmesh,capitalaslash/libmesh,giorgiobornia/libmesh,permcody/libmesh,dknez/libmesh,cahaynes/libmesh,dmcdougall/libmesh,dmcdougall/libmesh,coreymbryant/libmesh,dschwen/libmesh,giorgiobornia/libmesh,friedmud/libmesh,coreymbryant/libmesh,coreymbryant/libmesh,BalticPinguin/libmesh,svallaghe/libmesh,friedmud/libmesh,roystgnr/libmesh,pbauman/libmesh,jiangwen84/libmesh,dknez/libmesh,pbauman/libmesh,hrittich/libmesh,jiangwen84/libmesh,90jrong/libmesh,dmcdougall/libmesh,balborian/libmesh,coreymbryant/libmesh,vikramvgarg/libmesh,giorgiobornia/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,BalticPinguin/libmesh,hrittich/libmesh,benkirk/libmesh,aeslaughter/libmesh,benkirk/libmesh,friedmud/libmesh,balborian/libmesh,dschwen/libmesh,coreymbryant/libmesh,balborian/libmesh,capitalaslash/libmesh,dknez/libmesh,aeslaughter/libmesh,aeslaughter/libmesh,roystgnr/libmesh,capitalaslash/libmesh,hrittich/libmesh,dmcdougall/libmesh,balborian/libmesh,BalticPinguin/libmesh,jwpeterson/libmesh,dschwen/libmesh,benkirk/libmesh,benkirk/libmesh,dschwen/libmesh